Sheffield provides the setting for The Friendly Ones. Photograph: Alamy

Like his Man Booker-shortlisted 2008 novel The Northern Clemency, Philip Hensher’s new book is set in Sheffield and describes the lives of two families over recent decades. And like his semi-biographical Scenes from Early Life, it includes many descriptions of the 1971 war of liberation in Bangladesh. While the Spinster family is white and English, like Hensher’s own, their neighbours the Sharifullahs are, like his husband, from Dhaka.

In keeping with Hensher’s recent output, the novel is an ample work: 624 dense pages are stuffed with an immense cast of characters. There are lengthy journeys by train and car, many very detailed meals, and buckets of chat. The setting is bulked out with quantities of period detail – Hensher is especially good on interior design, and snacks – and the whole is ornamented by outbursts of mellifluous description. “A bird was singing in the elm tree, a loud, plangent, lovely note, as if asking a question of the garden,” for example, sets the scene in the opening chapter, a party where light dapples “the lawn, the red box of the barbecue, the white-shirted help”. Both families, as that mention of “help” suggests, are thoroughly upper-middle class.

Such an ocean of the quotidian quickly becomes muddling, especially because Hensher is unusually willing to create characters in depth, then throw them away. Why, we ask ourselves, must we spend the first three chapters with a melancholy Italian academic with the smallest of bit parts to play? Why waste 40 pages on buying sweets from a man named Abdul and joking with a flatmate called Sonia who will never appear again? Even the central characters are confusingly alike: they have similar lonely, nasty childhood experiences at the hands of small bullies, and grow into arty adults with detached, ironical casts of mind. Everyone, even in extreme circumstances, banters like an English gent.

Such an ocean of the quotidian quickly becomes muddling as Hensher creates characters in depth, then throws them away

We are soon gasping for a plot; Hensher offers two. His novel is based, he tell us in the acknowledgments, on Pushkin’s Eugene Onegin and Shakespeare’s The Winter’s Tale. You can see why: they are both stories with long time lapses, themes of love, loss and violence, and feature characters trapped in the mores of their times. But they are also highly literary, non-naturalistic romances in verse with deliberately arbitrary plots, and the imposition of these on Hensher’s strenuous superrealism is odd indeed. By the time Aisha Sharifullah, who appears to be echoing Pushkin’s Tatiana, sits down to write her romantic declaration to Leo Spinster, she has been characterised as a liberated 1980s young woman who invites boyfriends to stay for the weekend with her westernised, agnostic parents. So for her to write a love letter, unlike for Tatiana, is neither transgressive nor dangerous. Leo’s rebuff is equally lacking in charge and his subsequent lifetime’s regret is overblown. Though perhaps not as overblown as his own Winter’s Tale-like exile for the crime of having – whisper it – dropped out of Oxford. This is hard to take seriously, especially when it seems to be being compared to the tragedy of losing a brother in the Bangladesh war.

But at least Aisha’s letter is an event between the families. Otherwise, the characters have remarkably little to do with one another. The two families have each other round for meals, and watch their children’s and grandchildren’s lives develop on courses that may be buffeted by history, but are essentially separate. As the novel wears on, these unfoldings reveal schematic parallels: the Sharifullahs outdo their white neighbours in the game of degrees, careers and property acquired. And virtue, too, since the Bengali family are in every way what Nikesh Shukla dubbed the “good immigrant”: injured in a distant war, educated, striving, integrated, grateful.

This is a fine lesson, but as a plot for a bulky novel it is thin. Too much of our time is taken up with illustration, not action. Abdul and Sonia, for example, appear to be in the book as types of multicultural Britain: Abdul the assiduous Kashmiri shop keeper, Sonia the feisty Jamaican woman. Enrico the Italian academic takes up pages and pages purely to illustrate European politics, be a minor foil for Aisha, and to be dull, which he is, all too successfully.

Nor, for all its apparent ambition in this direction, is Hensher’s landscape truly representative of multicultural Britain. Conspicuously, there is no space for Pakistanis, and precious little for Islam, either, for none of the nominally Muslim characters articulates any kind of religious thought. Even when we take a holiday with Mahfouz, who is to become an Islamist fanatic, we hear only the usual burble about the view from the train and the quality of the food. When he thinks about the Sharifullahs, his poor mind simply slides away from their liberal greatness: “He would not know how to begin to forgive Sharif for being Sharif, for being humorous and singing about the place, an old Tagore song, a funny old song he had just heard.” Mahfouz’s veiled wives, noticeably in this chattering world, are not allowed a voice.

Non-middle-class migrants, too, are silent, that “white shirted help”, perhaps, standing object-like by the barbecue. We get one glimpse of the lives of poor Indians in Sheffield when Aisha goes on a visit with a white friend, then she moves uncomprehendingly on. For a more challenging view of Sheffield in the last quarter-century, and some understanding of people smuggling, sweated labour, Asian women, and other faiths, you might read Sunjeev Sahota’s The Year of the Runaways instead.

Kate Clanchy’s The Not-Dead and the Saved is published by Picador. The Friendly Ones by Philip Hensher (4th Estsate, £14.99). To order a copy for £12.74, go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min. p&p of £1.99.

This review was edited on Monday 12 March to correct the spelling of Mafouz to Mahfouz.